<?php
/**
 * Handles a string attribute that may also be missing.
 *
 * PHP version 5
 *
 * @category Kolab
 * @package  Kolab_Format
 * @author   Gunnar Wrobel <wrobel@pardus.de>
 * @license  http://www.horde.org/licenses/lgpl21 LGPL
 * @link     http://www.horde.org/libraries/Horde_Kolab_Format
 */

/**
 * Handles a string attribute that may also be missing.
 *
 * Copyright 2011-2016 Horde LLC (http://www.horde.org/)
 *
 * See the enclosed file COPYING for license information (LGPL). If you did not
 * receive this file, see
 * http://www.horde.org/licenses/lgpl21.
 *
 * @category Kolab
 * @package  Kolab_Format
 * @author   Gunnar Wrobel <wrobel@pardus.de>
 * @license  http://www.horde.org/licenses/lgpl21 LGPL
 * @link     http://www.horde.org/libraries/Horde_Kolab_Format
 */
class Horde_Kolab_Format_Xml_Type_String_MaybeMissing
extends Horde_Kolab_Format_Xml_Type_Base
{
    /**
     * Load the value of a node.
     *
     * @param DOMNode                       $node   Retrieve value for this node.
     * @param Horde_Kolab_Format_Xml_Helper $helper A XML helper instance.
     * @param array                         $params Additiona parameters for
     *                                              this parse operation.
     *
     * @return mixed|null The value or null if no value was found.
     */
    public function loadNodeValue(
        $node,
        Horde_Kolab_Format_Xml_Helper $helper,
        $params = array()
    )
    {
        $result = $helper->fetchNodeValue($node);
        if ($result === null) {
            $result = '';
        }
        return $result;
    }

    /**
     * Update the specified attribute.
     *
     * @param string                        $name        The name of the the
     *                                                   attribute to be updated.
     * @param array                         $attributes  The data array that holds
     *                                                   all attribute values.
     * @param DOMNode                       $parent_node The parent node of the
     *                                                   node that should be
     *                                                   updated.
     * @param Horde_Kolab_Format_Xml_Helper $helper      A XML helper instance.
     * @param array                         $params      Additional parameters
     *                                                   for this write operation.
     *
     * @return DOMNode|boolean The new/updated child node or false if this
     *                         failed.
     *
     * @throws Horde_Kolab_Format_Exception If converting the data to XML failed.
     */
    public function save(
        $name,
        $attributes,
        $parent_node,
        Horde_Kolab_Format_Xml_Helper $helper,
        $params = array()
    )
    {
        $node = $helper->findNodeRelativeTo(
            './' . $name, $parent_node
        );

        if (!isset($attributes[$name])) {
            if ($node !== false) {
                /** Client indicates that the value should get removed */
                $helper->removeNodes($parent_node, $name);
            }
            return false;
        }

        return $this->saveNodeValue(
            $name,
            $this->generateWriteValue($name, $attributes, $params),
            $parent_node,
            $helper,
            $params,
            $node
        );
    }

    /**
     * Generate the value that should be written to the node. Override in the
     * extending classes.
     *
     * @param string  $name        The name of the the attribute
     *                             to be updated.
     * @param array   $attributes  The data array that holds all
     *                             attribute values.
     * @param array   $params      The parameters for this write operation.
     *
     * @return mixed The value to be written.
     */
    protected function generateWriteValue($name, $attributes, $params)
    {
        return $attributes[$name];
    }
}
